Sensors collect data to transmit indoor and outdoor temperatures, wind chill/gusts/speed, barometric pressure with 12-hour tendency, dew point and humidity, as well as the minimum/maximum/time of these readings to the indoor display. Also displays storm warning indicator, time in 12- or 24-hour mode and calendar. Weather history display shows a record of all values saved every three hours up to a total of 140 records. The outdoor sensor can be positioned up to 330 ft. away. Indoor display can be used free-standing or mounted on a wall. Receiver uses two C alkaline batteries and the sensor uses two AA alkaline batteries (not included). Batteries last up to 24 months. Receiver: 5.83"H x 5.83"W x 2"D. Wind sensor: 9.8"H x 5.7"W x 7.5"D. Thermo-Hygro: 6.18"H x 2.44"W x 2.26"D.